• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.2
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• pp.134-143
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• 2001

This paper presents the characteristics of flank and tip seal leakage in a scroll compressor for air-conditioners with R-22 under actual operating conditions. It is well known that the leakage has significant effect on the performance of the scroll compressor. Experiments were performed by using indirect method for measuring mass flow rate passing through flank and tip seal under actual operating conditions, In addition, an analytical model for tip seal leakage was developed to investigate tangential and radial leakage observed at grooves and contact points of tip seals. For low oil concentration, theoretical results were compared with experimental data to verify the analytical model. As a result, leakages through flank and tip seal parts were evaluated as afunction of pressure ratio, orbiting angle, discharge pressure, tip clearance, and leakage point. It was also found that the tip seal leakage was considerable even though the tip seal provided adequate sealing effect.

• Journal of Climate Change Research
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• v.8 no.2
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• pp.81-89
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• 2017

In this study CALPUFF was used to estimate the influence of temperature rise, according to the observation value of temperature rise based RCP scenario, on meteorological elements (wind direction, wind speed, mixing height) and the change of pollutant diffusion. According to the result. applying estimated value of year 2050 temperature rise, the mixing height is increased as per the temperature rise, so the range of atmospheric diffusion is widened. In summer case, by applying temperature rise of $4^{\circ}C$ and comparing with before applying temperature rise, there was change of diffusion range as per the change of temperature between 10 AM to 11 PM. And the range of diffusion was wider than that of before temperature rise. In winter case, by applying estimated value of temperature rise, $2.3^{\circ}C$, diffusion range has been changed between 8 AM to 4 PM, showing different diffusion aspect from summer. Also, according to the result of air pollution level assessment with temperature rise, it was proved that the ratio of area with increasing air pollution level has been getting higher by increase of temperature.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.3
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• pp.1-9
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• 2023

The overall Air Force's serious accident rate is decreasing, but the trainer's accident rate is on the rise from 0.24% in '00~'09 to 0.77% in '01~'19. Base on the SHELL model recommended by the ICAO, the risk factors of the introductory flight training course were analyzed, implications were examined, and safety promotion measures were proposed. A survey of 25 questions was organized based on regulations, guidelines, and related data for each component of the SHELL model in accordance with the introductory course of Air Force flight training. The survey was divided into a student group and instructor group and compared and analyzed into L-L, L-S, L-H, and L-E based on the results after conducting it, and implications for this were derived. Compared to other analysis factors, L-L showed that the average of the instructor group was relatively higher that of the student group in all questions.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.43-50
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• 2006

The major objective of this paper is to propose a hybrid simulation environment for autonomous UAV system by integrating the continuous-time model with discrete-event model. Proposed system is able to support high autonomous behavior by combining the planner, recognizer, and controller model to deal with the HL20 AIRPLANE model. Thus, the high level decision may be efficiently issued even upon the unexpected circumstance. The proposed system model has been successfully verified by several simulation test performed on the DEVS simulation S/W environment.

• Elastomers and Composites
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• v.45 no.4
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• pp.250-255
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• 2010

From the three element non-Newtonian model of one non-Newtonian viscoelastic Maxwell elements and a elastic spring, the stress relaxation equation was derived. The various model parameters of this equation were evaluated by appling the experimental results of stress relaxation to the stress relaxation equation. The theoretical curves calculated from this model parameters agreed with the experimental stress relaxation curves. From the parameters of nonlinear viscoelastic model, the hole volume, fine structure, viscoelastic properties and mechanical properties of polymer fibers were studied. The experiments of stress relaxation were carried out using the tensile tester with the solvent chamber. The stress relaxation curves of the two types polyacrylonitrile-polyvinylchloride copolymer and another two types PVC monofilament fibers were obtained in air and water of various temperatures.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.480-483
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• 2006

The purpose of this study was to examine the spatial composition and characteristics of model houses that have recently opened in Pangyone ara. Site visit and content analysis were adopted in this study. and the studied model houses developed by nine housing were of particular interest. The major findings indicated that convenience and safety through high tech-related features, environmentally friendly features in response to the growing attention of consumers to indoor air quality, aesthetic building facade and its various floor plan, and a wide range of consumers choice for interior finishes and materials. The new trends provides a flexible wall which makes it possible to manipulate the number of rooms according to the family preference.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1276-1293
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• 1993

A numerical and experimental flow visualization study of the louvered fin array, commonly used in a compact heat exchanger was performed. The flow structure which was obtained by using a finite difference method, was compared with an experimental result. The experimental flow visualization was performed by using a dye injection technique with 13:1 scale model. The effects of Reynolds number and fin geometries on flow structure and heat transfer were examined.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.E
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• pp.390-396
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• 1993

An acid deposition Engineering Model was developed by parameterizing the role of organics in the photochemistry and by simplifying liquid phase processes. This Engineering Model concept was implemented onto the Sulfur Transport Eulerian Model II(STEM II). The Engineering Model version of the STEM(STEM-ENG) saves the CPU time over 50 times and produces the upper and lower limit values prodicted by the original STEM II. These limits obtained by the STEM-ENG can be used to estimate the importance of organics in acid and O3 production. The STEM-ENG with 30,000 grid points can be run on any recent PCs to give a quick assessment of air quality.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.76-82
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• 2006

본 연구는 항공기 관제사의 관제디스플레이에 대한 생태학적 인터페이스 디자인을 적용하기 위한 초기작업으로써 항공기 관제영역에 대한 Work Domain Analysis 를 실시하여 Work Domain Model 을 개발하고 모델에 대한 테스트를 통해 모델의 타당성을 검증하였다. 또한, 완성된 모델을 바탕으로 디자인을 위한 Information Requirement 를 추출함으로써 지금까지 적용해보지 않은 항공기 관제영역에 대한 생태학적 인터페이스 디자인 툴(Tool)의 새로운 적용가능성을 확인하여 추후, 구체적인 관제 디스플레이의 생태학적 개발에 기본 틀을 제공하고자 한다.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.3-9
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• 2003

By utilizing a semi-empirical soot model, the applicability of the laminar flamelet concept for simulating the formation and oxidation of soot in the laminar diffusion flame has been studied. The source terms for two transport equations of the soot formation and oxidation are calculated in the mixture fraction/scalar dissipation rate space for laminar flamelets and stored in a library. In this study, emphasis is given to the interaction associated with radiation and soot formation. The radiative heat loss is obtained by solving the radiative transfer equation using the unstructured grid finite volume method with the WSGGM. The calculated temperatures and soot volume fractions agree relatively well with the experimental data and the previous numerical results of Kaplan et al. using the detailed chemistry.